Extracellular ATP receptors P2Ks are involved in regulating local and systemic stomatal responses to local...

Extracellular ATP (exATP) and its receptors play important roles in the regulation of the responses of plants to environmental stimulation. The lectin receptor kinases I.9 (P2K1) and I.5 (P2K2) are known as the receptors of exATP in Arabidopsis thaliana. The change of stomata aperture can show adaptive relationships to the environmental conditions surrounding the plant. However, when plants are exposed to local environmental stimuli, whether the exATP level has the systemic characteristic change and regulates stomata aperture by binding its receptors is still poorly studied. The present work showed that local environmental stimuli (including wounding, high light stress, dark-to-light transition and heat stress) in Arabidopsis thaliana triggered an increase of exATP level not only in the local leaf but also in the systemic leaves. By using p2k1 single-mutant, p2k2 single-mutant, and p2k1/p2k2 double-mutant plants, it was found that the local environmental stimuli-induced stomatal response was weakened or attenuated not only in the local leaf but also in systemic leaves in P2Ks mutants. These results indicate that exATP/P2Ks are involved in regulating local and systemic stomatal responses to local environmental stimuli.